On Tue, Jun 1, 2010 at 12:16 PM, Ken Nielson
<knielson at adaptivecomputing.com> wrote:
> On 06/01/2010 10:08 AM, Felix Werner wrote:
>> Dear all,
>>>> Suppose I want to run a job on 40 CPUs (with MPI),
>> and there are
>> 10 CPUs available on the node "node1"
>> 10 on "node2"
>> 20 on "node3".
>>>> What I do is:
>>>> qsub -l nodes=node1:ppn=10+node2:ppn=10+node3:ppn=20 shell_name.sh
>>>> This is tedious because I need to look manually how many CPUs are
>> available on which node.
>>>> So is there a way to just tell the queing system "I want to run on 40
>> CPUs, on whatever nodes"?
>>>> Many thanks!
>>>> Felix Werner
>>>>> Felix,
>> If you use a scheduler like Moab you can simply use qsub -l nodes=40 and
> it will take care of where they are going to run. But if you are going
> to run jobs manually this is how it has to be done.
>
one thing to note is that if you have fewer than 40 nodes you need to
trick TORQUE into thinking you have more nodes than it really has so
that it doesn't reject a request like -l nodes=40. Moab treats a
nodes=X request without a ppn=Y component as a request stating "I just
need X processors".
You can also do -l procs=40, which doesn't require configuring TORQUE
to think it has more nodes than it actually has. This is only
supported with Moab.